Columbian Exchange: This was a widespread exchange of animals, plants, culture, human populations, diseases, technology and ideas between American and Afro-Eurasian hemispheres following Columbus's voyages. It’s like a school fair where everyone brings something unique from their background to share.
Irish Immigration: This refers to the movement of people from Ireland to other parts of the world; in US history context it often refers specifically to mass migration during the Great Famine. It’s similar to students transferring schools due to various reasons.
Great Famine (Ireland): A period of mass starvation and disease in Ireland from 1845-1852 caused by potato blight. It's akin to an unexpected event that disrupts normal school routine - like a power outage causing cancellation of classes.